The present invention relates generally to methods and apparatus for use while charging lubricant retaining and wicking material in consistent amounts cleanly and with a minimum amount of messiness into bearing lubricant reservoirs--such as, for example bearing reservoirs of fractional horsepower motors.
The above-referenced applications describe many of the problems in the material handling and moving application art, and especially the art concerning materials that are readily compressible or damaged during handling or dispensing operations. Materials of the type of primary consideration when considering the present invention are those that are made, for example, according to the commonly assigned Whitt U.S. Pat. No. 3,894,956 which issued July 15, 1975; and those made pursuant to Abel U.S. Pat. No. 2,966,459 of Dec. 27, 1960 or other materials marketed under the trade name "Permawick" by the Permawick Company Inc. There are numerous patents in the art related to injectable lubricating material in addition to the Whitt and Abel patents mentioned hereinabove. For example, Abel U.S. Pat. No. 3,466,244 which issued Sept. 9, 1969; and Abel U.S. Pat. No. 3,226,801 which issued Jan. 4, 1966 describe materials, and equipment for producing materials, respectively.
Historically, equipment utilized for injecting or metering flowable wicking and lubricating materials has been available commercially from the Permawick Company (or companies affiliated with Permawick) and in such equipment, a metering head having a nozzle is lowered into position with the lubricant retaining reservoir of a dynamoelectric machine end shield. At the end of an injection cycle, the nozzle is then raised from the end shield structure and preparation is made for for injecting lubricant retaining and wicking material into another dynamoelectric machine end shield.
The lubricating materials used typically include a lubricant mixed with a lubricant retaining material--such material being referred to herein as a carrier or matrix material. I have found that when commercially available equipment is used for injecting this type of material, it is difficult to accurately and precisely control the flow of material (or oil, per se) at the end of a dispensing cycle. More specifically, I have observed that this type of material will tend to ooze or exude from the prior art nozzles and contribute to messy work locations. In addition, with some product lines, the presence of excess oil or exudate from the nozzle on an end shield would be very objectionable to a purchaser of motors utilizing such end shield and time and labor must be expended in order to remove the excess oil or other exudate from the end shield. It is believed that part of this problem is associated with the fact that the oil and matrix material is extruded from small openings and the flow of the material being extruded does not respond instantaneously to the removal of extrusion pressures therefrom.
Accordingly, it would be desirable to provide new and improved methods of cutting off the flow of extrudable lubricants, and apparatus useful in practicing such methods; so that unwanted exudates may be minimized or eliminated. It would be particularly desirable to provide such methods and apparatus which could be easily utilized in conjunction with the methods and apparatus known in the prior art as well as the methods and apparatus described in the above-referenced Stoner application and the above-reference Tomson and Bohde application. It would also be desirable to provide new and improved nozzle flow control techniques for materials of the type under consideration herein which could be utilized easily and economically with various end frames.